FIGURE 3.

Co-immunoprecipitation of wt or mutant IL-31 with sGPL-Fc or sOSMR-Fc. All proteins were produced in the Cos-7 cell system. Cell culture supernatant of Il-31 mutants was diluted to a final concentration of 300 ng/ml. Soluble receptors were incubated in the presence of 300 ng/ml of cytokines overnight at 4 °C before being immunoprecipitated with protein A beads. IL-31 association was detected using a monoclonal anti-V5 antibody or OSM with a biotinylated polyclonal anti-OSM antibody. Soluble receptors fused to the IgG1 Fc fragment were detected with an anti-Fc antibody. WB, Western blot; IP, immunoprecipitation; W.T., wild type.